1. Field of the Invention
The present invention pertains to centrifuges.
2. Discussion of Related Art
Fluids, such as whole blood or various other biological fluids are suspensions and can be separated into their constituent parts or fractions. For example, whole blood comprises four main fractions, red blood cells, white blood cells, platelets and plasma, that can be separated based on their different specific gravities in a device such as a centrifuge. An anti-coagulated whole blood sample may be placed in a test tube, or other similar device, which is then spun in a centrifuge at a specified speed. The generated centrifugal force separates the blood into the different fractions based on their relative specific gravities. The red blood cells are on the bottom, plasma, is on the top with the intermediate specific gravity white blood cells and platelets intermediate to the other two fractions. Various other biological fluids may be separated as well. For example, nucleated cells may be separated and extracted from bone marrow or adipose tissue derived samples.
It is desirable to isolate the different fractions of whole blood for differing medicinal purposes. The platelets can be obtained in preparations of platelet rich plasma (PRP) or platelet concentrates (PC). Platelets contain growth factors (e.g. PDGF, TGF-β, and others), which may initiate, aid in or accelerate various bodily functions, including but not limited to angiogenesis, wound healing, and osteogenesis. Administering autologous platelets to an injury site may improve the healing response by using a patient's own platelets without the risk of infection by using blood products from another donor source.
Various systems exist for the production of PRP/PC. Some use specialized test tubes, U.S. Pat. Nos. 7,179,391 and 7,520,402, that can include floats, tubing and/or gel materials of specific densities. Other systems use specialized double syringes, for example those found in U.S. Pat. Nos. 6,716,187 and 7,195,606. These test tubes and syringes must be centrifuged in a specialized large centrifuge for a specified time, typically 10-30 minutes, and then by delicate handling and extraction or decanting procedures produce the desired PRP/PC. The consistency of these preparations can vary depending on the operator's skill level. Other systems, for example U.S. Pat. No. 6,982,038, contain specialized centrifuge chambers and complicated control systems to produce the PRP/PC in about 30 minutes. All of these systems provide PRP/PC of differing platelet concentrations depending on the method used. A major drawback to these methods is the need for an expensive piece of capital equipment which limits the utility to facilities that have the funds and space available. These methods also require considerable operator skills to complete the procedures necessary to obtain the PRP/PC.
The ability to produce PRP/PC from a patient's own blood at the point of care without the need for complex, expensive equipment and difficult procedures would facilitate the clinical utility of PRP/PC. Therefore the objects of this invention include among other things providing an apparatus and method for processing a patient's own blood at the point of care in a short period of time that is self contained, battery operated, small and or portable, inexpensive, easy to use, reproducible, able to separate many cellular populations, and disposable without the need for additional centrifugation equipment